Add spellcheck and word suggestion to the prediction service

third_party/android_prediction/suggest/core/layout/proximity_info_state_utils.cpp

Index: third_party/android_prediction/suggest/core/layout/proximity_info_state_utils.cpp
diff --git a/third_party/android_prediction/suggest/core/layout/proximity_info_state_utils.cpp b/third_party/android_prediction/suggest/core/layout/proximity_info_state_utils.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..d80be6263fe16678158450b2d26baec33065885a
--- /dev/null
+++ b/third_party/android_prediction/suggest/core/layout/proximity_info_state_utils.cpp
@@ -0,0 +1,1015 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "third_party/android_prediction/suggest/core/layout/proximity_info_state_utils.h"
+
+#include <algorithm>
+#include <cmath>
+#include <cstring> // for memset()
+#include <sstream> // for debug prints
+#include <unordered_map>
+#include <vector>
+
+#include "third_party/android_prediction/defines.h"
+#include "third_party/android_prediction/suggest/core/layout/geometry_utils.h"
+#include "third_party/android_prediction/suggest/core/layout/normal_distribution_2d.h"
+#include "third_party/android_prediction/suggest/core/layout/proximity_info.h"
+#include "third_party/android_prediction/suggest/core/layout/proximity_info_params.h"
+
+namespace latinime {
+
+/* static */ int ProximityInfoStateUtils::trimLastTwoTouchPoints(std::vector<int> *sampledInputXs,
+        std::vector<int> *sampledInputYs, std::vector<int> *sampledInputTimes,
+        std::vector<int> *sampledLengthCache, std::vector<int> *sampledInputIndice) {
+    const int nextStartIndex = (*sampledInputIndice)[sampledInputIndice->size() - 2];
+    popInputData(sampledInputXs, sampledInputYs, sampledInputTimes, sampledLengthCache,
+            sampledInputIndice);
+    popInputData(sampledInputXs, sampledInputYs, sampledInputTimes, sampledLengthCache,
+            sampledInputIndice);
+    return nextStartIndex;
+}
+
+/* static */ int ProximityInfoStateUtils::updateTouchPoints(
+        const ProximityInfo *const proximityInfo, const int maxPointToKeyLength,
+        const int *const inputProximities, const int *const inputXCoordinates,
+        const int *const inputYCoordinates, const int *const times, const int *const pointerIds,
+        const int inputSize, const bool isGeometric, const int pointerId,
+        const int pushTouchPointStartIndex, std::vector<int> *sampledInputXs,
+        std::vector<int> *sampledInputYs, std::vector<int> *sampledInputTimes,
+        std::vector<int> *sampledLengthCache, std::vector<int> *sampledInputIndice) {
+    if (DEBUG_SAMPLING_POINTS) {
+        if (times) {
+            for (int i = 0; i < inputSize; ++i) {
+                AKLOGI("(%d) x %d, y %d, time %d",
+                        i, inputXCoordinates[i], inputYCoordinates[i], times[i]);
+            }
+        }
+    }
+#ifdef DO_ASSERT_TEST
+    if (times) {
+        for (int i = 0; i < inputSize; ++i) {
+            if (i > 0) {
+                if (times[i] < times[i - 1]) {
+                    AKLOGI("Invalid time sequence. %d, %d", times[i - 1], times[i]);
+                    ASSERT(false);
+                }
+            }
+        }
+    }
+#endif
+    const bool proximityOnly = !isGeometric
+            && (inputXCoordinates[0] < 0 || inputYCoordinates[0] < 0);
+    int lastInputIndex = pushTouchPointStartIndex;
+    for (int i = lastInputIndex; i < inputSize; ++i) {
+        const int pid = pointerIds ? pointerIds[i] : 0;
+        if (pointerId == pid) {
+            lastInputIndex = i;
+        }
+    }
+    if (DEBUG_GEO_FULL) {
+        AKLOGI("Init ProximityInfoState: last input index = %d", lastInputIndex);
+    }
+    // Working space to save near keys distances for current, prev and prevprev input point.
+    NearKeysDistanceMap nearKeysDistances[3];
+    // These pointers are swapped for each inputs points.
+    NearKeysDistanceMap *currentNearKeysDistances = &nearKeysDistances[0];
+    NearKeysDistanceMap *prevNearKeysDistances = &nearKeysDistances[1];
+    NearKeysDistanceMap *prevPrevNearKeysDistances = &nearKeysDistances[2];
+    // "sumAngle" is accumulated by each angle of input points. And when "sumAngle" exceeds
+    // the threshold we save that point, reset sumAngle. This aims to keep the figure of
+    // the curve.
+    float sumAngle = 0.0f;
+
+    for (int i = pushTouchPointStartIndex; i <= lastInputIndex; ++i) {
+        // Assuming pointerId == 0 if pointerIds is null.
+        const int pid = pointerIds ? pointerIds[i] : 0;
+        if (DEBUG_GEO_FULL) {
+            AKLOGI("Init ProximityInfoState: (%d)PID = %d", i, pid);
+        }
+        if (pointerId == pid) {
+            const int c = isGeometric ?
+                    NOT_A_COORDINATE : getPrimaryCodePointAt(inputProximities, i);
+            const int x = proximityOnly ? NOT_A_COORDINATE : inputXCoordinates[i];
+            const int y = proximityOnly ? NOT_A_COORDINATE : inputYCoordinates[i];
+            const int time = times ? times[i] : -1;
+
+            if (i > 1) {
+                const float prevAngle = GeometryUtils::getAngle(
+                        inputXCoordinates[i - 2], inputYCoordinates[i - 2],
+                        inputXCoordinates[i - 1], inputYCoordinates[i - 1]);
+                const float currentAngle = GeometryUtils::getAngle(
+                        inputXCoordinates[i - 1], inputYCoordinates[i - 1], x, y);
+                sumAngle += GeometryUtils::getAngleDiff(prevAngle, currentAngle);
+            }
+
+            if (pushTouchPoint(proximityInfo, maxPointToKeyLength, i, c, x, y, time,
+                    isGeometric, isGeometric /* doSampling */, i == lastInputIndex,
+                    sumAngle, currentNearKeysDistances, prevNearKeysDistances,
+                    prevPrevNearKeysDistances, sampledInputXs, sampledInputYs, sampledInputTimes,
+                    sampledLengthCache, sampledInputIndice)) {
+                // Previous point information was popped.
+                NearKeysDistanceMap *tmp = prevNearKeysDistances;
+                prevNearKeysDistances = currentNearKeysDistances;
+                currentNearKeysDistances = tmp;
+            } else {
+                NearKeysDistanceMap *tmp = prevPrevNearKeysDistances;
+                prevPrevNearKeysDistances = prevNearKeysDistances;
+                prevNearKeysDistances = currentNearKeysDistances;
+                currentNearKeysDistances = tmp;
+                sumAngle = 0.0f;
+            }
+        }
+    }
+    return sampledInputXs->size();
+}
+
+/* static */ const int *ProximityInfoStateUtils::getProximityCodePointsAt(
+        const int *const inputProximities, const int index) {
+    return inputProximities + (index * MAX_PROXIMITY_CHARS_SIZE);
+}
+
+/* static */ int ProximityInfoStateUtils::getPrimaryCodePointAt(const int *const inputProximities,
+        const int index) {
+    return getProximityCodePointsAt(inputProximities, index)[0];
+}
+
+/* static */ void ProximityInfoStateUtils::initPrimaryInputWord(const int inputSize,
+        const int *const inputProximities, int *primaryInputWord) {
+    memset(primaryInputWord, 0, sizeof(primaryInputWord[0]) * MAX_WORD_LENGTH);
+    for (int i = 0; i < inputSize; ++i) {
+        primaryInputWord[i] = getPrimaryCodePointAt(inputProximities, i);
+    }
+}
+
+/* static */ float ProximityInfoStateUtils::calculateSquaredDistanceFromSweetSpotCenter(
+        const ProximityInfo *const proximityInfo, const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs, const int keyIndex, const int inputIndex) {
+    const float sweetSpotCenterX = proximityInfo->getSweetSpotCenterXAt(keyIndex);
+    const float sweetSpotCenterY = proximityInfo->getSweetSpotCenterYAt(keyIndex);
+    const float inputX = static_cast<float>((*sampledInputXs)[inputIndex]);
+    const float inputY = static_cast<float>((*sampledInputYs)[inputIndex]);
+    return GeometryUtils::SQUARE_FLOAT(inputX - sweetSpotCenterX)
+            + GeometryUtils::SQUARE_FLOAT(inputY - sweetSpotCenterY);
+}
+
+/* static */ float ProximityInfoStateUtils::calculateNormalizedSquaredDistance(
+        const ProximityInfo *const proximityInfo, const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs, const int keyIndex, const int inputIndex) {
+    if (keyIndex == NOT_AN_INDEX) {
+        return ProximityInfoParams::NOT_A_DISTANCE_FLOAT;
+    }
+    if (!proximityInfo->hasSweetSpotData(keyIndex)) {
+        return ProximityInfoParams::NOT_A_DISTANCE_FLOAT;
+    }
+    if (NOT_A_COORDINATE == (*sampledInputXs)[inputIndex]) {
+        return ProximityInfoParams::NOT_A_DISTANCE_FLOAT;
+    }
+    const float squaredDistance = calculateSquaredDistanceFromSweetSpotCenter(proximityInfo,
+            sampledInputXs, sampledInputYs, keyIndex, inputIndex);
+    const float squaredRadius = GeometryUtils::SQUARE_FLOAT(
+            proximityInfo->getSweetSpotRadiiAt(keyIndex));
+    return squaredDistance / squaredRadius;
+}
+
+/* static */ void ProximityInfoStateUtils::initGeometricDistanceInfos(
+        const ProximityInfo *const proximityInfo, const int sampledInputSize,
+        const int lastSavedInputSize, const bool isGeometric,
+        const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs,
+        std::vector<float> *sampledNormalizedSquaredLengthCache) {
+    const int keyCount = proximityInfo->getKeyCount();
+    sampledNormalizedSquaredLengthCache->resize(sampledInputSize * keyCount);
+    for (int i = lastSavedInputSize; i < sampledInputSize; ++i) {
+        for (int k = 0; k < keyCount; ++k) {
+            const int index = i * keyCount + k;
+            const int x = (*sampledInputXs)[i];
+            const int y = (*sampledInputYs)[i];
+            const float normalizedSquaredDistance =
+                    proximityInfo->getNormalizedSquaredDistanceFromCenterFloatG(
+                            k, x, y, isGeometric);
+            (*sampledNormalizedSquaredLengthCache)[index] = normalizedSquaredDistance;
+        }
+    }
+}
+
+/* static */ void ProximityInfoStateUtils::popInputData(std::vector<int> *sampledInputXs,
+        std::vector<int> *sampledInputYs, std::vector<int> *sampledInputTimes,
+        std::vector<int> *sampledLengthCache, std::vector<int> *sampledInputIndice) {
+    sampledInputXs->pop_back();
+    sampledInputYs->pop_back();
+    sampledInputTimes->pop_back();
+    sampledLengthCache->pop_back();
+    sampledInputIndice->pop_back();
+}
+
+/* static */ float ProximityInfoStateUtils::refreshSpeedRates(const int inputSize,
+        const int *const xCoordinates, const int *const yCoordinates, const int *const times,
+        const int lastSavedInputSize, const int sampledInputSize,
+        const std::vector<int> *const sampledInputXs, const std::vector<int> *const sampledInputYs,
+        const std::vector<int> *const sampledInputTimes,
+        const std::vector<int> *const sampledLengthCache,
+        const std::vector<int> *const sampledInputIndice, std::vector<float> *sampledSpeedRates,
+        std::vector<float> *sampledDirections) {
+    // Relative speed calculation.
+    const int sumDuration = sampledInputTimes->back() - sampledInputTimes->front();
+    const int sumLength = sampledLengthCache->back() - sampledLengthCache->front();
+    const float averageSpeed = static_cast<float>(sumLength) / static_cast<float>(sumDuration);
+    sampledSpeedRates->resize(sampledInputSize);
+    for (int i = lastSavedInputSize; i < sampledInputSize; ++i) {
+        const int index = (*sampledInputIndice)[i];
+        int length = 0;
+        int duration = 0;
+
+        // Calculate velocity by using distances and durations of
+        // ProximityInfoParams::NUM_POINTS_FOR_SPEED_CALCULATION points for both forward and
+        // backward.
+        const int forwardNumPoints = std::min(inputSize - 1,
+                index + ProximityInfoParams::NUM_POINTS_FOR_SPEED_CALCULATION);
+        for (int j = index; j < forwardNumPoints; ++j) {
+            if (i < sampledInputSize - 1 && j >= (*sampledInputIndice)[i + 1]) {
+                break;
+            }
+            length += GeometryUtils::getDistanceInt(xCoordinates[j], yCoordinates[j],
+                    xCoordinates[j + 1], yCoordinates[j + 1]);
+            duration += times[j + 1] - times[j];
+        }
+        const int backwardNumPoints = std::max(0,
+                index - ProximityInfoParams::NUM_POINTS_FOR_SPEED_CALCULATION);
+        for (int j = index - 1; j >= backwardNumPoints; --j) {
+            if (i > 0 && j < (*sampledInputIndice)[i - 1]) {
+                break;
+            }
+            // TODO: use mSampledLengthCache instead?
+            length += GeometryUtils::getDistanceInt(xCoordinates[j], yCoordinates[j],
+                    xCoordinates[j + 1], yCoordinates[j + 1]);
+            duration += times[j + 1] - times[j];
+        }
+        if (duration == 0 || sumDuration == 0) {
+            // Cannot calculate speed; thus, it gives an average value (1.0);
+            (*sampledSpeedRates)[i] = 1.0f;
+        } else {
+            const float speed = static_cast<float>(length) / static_cast<float>(duration);
+            (*sampledSpeedRates)[i] = speed / averageSpeed;
+        }
+    }
+
+    // Direction calculation.
+    sampledDirections->resize(sampledInputSize - 1);
+    for (int i = std::max(0, lastSavedInputSize - 1); i < sampledInputSize - 1; ++i) {
+        (*sampledDirections)[i] = getDirection(sampledInputXs, sampledInputYs, i, i + 1);
+    }
+    return averageSpeed;
+}
+
+/* static */ void ProximityInfoStateUtils::refreshBeelineSpeedRates(const int mostCommonKeyWidth,
+        const float averageSpeed, const int inputSize, const int *const xCoordinates,
+        const int *const yCoordinates, const int *times, const int sampledInputSize,
+        const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs, const std::vector<int> *const inputIndice,
+        std::vector<int> *beelineSpeedPercentiles) {
+    if (DEBUG_SAMPLING_POINTS) {
+        AKLOGI("--- refresh beeline speed rates");
+    }
+    beelineSpeedPercentiles->resize(sampledInputSize);
+    for (int i = 0; i < sampledInputSize; ++i) {
+        (*beelineSpeedPercentiles)[i] = static_cast<int>(calculateBeelineSpeedRate(
+                mostCommonKeyWidth, averageSpeed, i, inputSize, xCoordinates, yCoordinates, times,
+                sampledInputSize, sampledInputXs, sampledInputYs, inputIndice) * MAX_PERCENTILE);
+    }
+}
+
+/* static */float ProximityInfoStateUtils::getDirection(
+        const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs, const int index0, const int index1) {
+    ASSERT(sampledInputXs && sampledInputYs);
+    const int sampledInputSize =sampledInputXs->size();
+    if (index0 < 0 || index0 > sampledInputSize - 1) {
+        return 0.0f;
+    }
+    if (index1 < 0 || index1 > sampledInputSize - 1) {
+        return 0.0f;
+    }
+    const int x1 = (*sampledInputXs)[index0];
+    const int y1 = (*sampledInputYs)[index0];
+    const int x2 = (*sampledInputXs)[index1];
+    const int y2 = (*sampledInputYs)[index1];
+    return GeometryUtils::getAngle(x1, y1, x2, y2);
+}
+
+// Calculating point to key distance for all near keys and returning the distance between
+// the given point and the nearest key position.
+/* static */ float ProximityInfoStateUtils::updateNearKeysDistances(
+        const ProximityInfo *const proximityInfo, const float maxPointToKeyLength, const int x,
+        const int y, const bool isGeometric, NearKeysDistanceMap *const currentNearKeysDistances) {
+    currentNearKeysDistances->clear();
+    const int keyCount = proximityInfo->getKeyCount();
+    float nearestKeyDistance = maxPointToKeyLength;
+    for (int k = 0; k < keyCount; ++k) {
+        const float dist = proximityInfo->getNormalizedSquaredDistanceFromCenterFloatG(k, x, y,
+                isGeometric);
+        if (dist < ProximityInfoParams::NEAR_KEY_THRESHOLD_FOR_DISTANCE) {
+            currentNearKeysDistances->insert(std::pair<int, float>(k, dist));
+        }
+        if (nearestKeyDistance > dist) {
+            nearestKeyDistance = dist;
+        }
+    }
+    return nearestKeyDistance;
+}
+
+// Check if previous point is at local minimum position to near keys.
+/* static */ bool ProximityInfoStateUtils::isPrevLocalMin(
+        const NearKeysDistanceMap *const currentNearKeysDistances,
+        const NearKeysDistanceMap *const prevNearKeysDistances,
+        const NearKeysDistanceMap *const prevPrevNearKeysDistances) {
+    for (NearKeysDistanceMap::const_iterator it = prevNearKeysDistances->begin();
+            it != prevNearKeysDistances->end(); ++it) {
+        NearKeysDistanceMap::const_iterator itPP = prevPrevNearKeysDistances->find(it->first);
+        NearKeysDistanceMap::const_iterator itC = currentNearKeysDistances->find(it->first);
+        const bool isPrevPrevNear = (itPP == prevPrevNearKeysDistances->end()
+                || itPP->second > it->second + ProximityInfoParams::MARGIN_FOR_PREV_LOCAL_MIN);
+        const bool isCurrentNear = (itC == currentNearKeysDistances->end()
+                || itC->second > it->second + ProximityInfoParams::MARGIN_FOR_PREV_LOCAL_MIN);
+        if (isPrevPrevNear && isCurrentNear) {
+            return true;
+        }
+    }
+    return false;
+}
+
+// Calculating a point score that indicates usefulness of the point.
+/* static */ float ProximityInfoStateUtils::getPointScore(const int mostCommonKeyWidth,
+        const int x, const int y, const int time, const bool lastPoint, const float nearest,
+        const float sumAngle, const NearKeysDistanceMap *const currentNearKeysDistances,
+        const NearKeysDistanceMap *const prevNearKeysDistances,
+        const NearKeysDistanceMap *const prevPrevNearKeysDistances,
+        std::vector<int> *sampledInputXs, std::vector<int> *sampledInputYs) {
+    const size_t size = sampledInputXs->size();
+    // If there is only one point, add this point. Besides, if the previous point's distance map
+    // is empty, we re-compute nearby keys distances from the current point.
+    // Note that the current point is the first point in the incremental input that needs to
+    // be re-computed.
+    if (size <= 1 || prevNearKeysDistances->empty()) {
+        return 0.0f;
+    }
+
+    const int baseSampleRate = mostCommonKeyWidth;
+    const int distPrev = GeometryUtils::getDistanceInt(sampledInputXs->back(),
+            sampledInputYs->back(), (*sampledInputXs)[size - 2],
+            (*sampledInputYs)[size - 2]) * ProximityInfoParams::DISTANCE_BASE_SCALE;
+    float score = 0.0f;
+
+    // Location
+    if (!isPrevLocalMin(currentNearKeysDistances, prevNearKeysDistances,
+        prevPrevNearKeysDistances)) {
+        score += ProximityInfoParams::NOT_LOCALMIN_DISTANCE_SCORE;
+    } else if (nearest < ProximityInfoParams::NEAR_KEY_THRESHOLD_FOR_POINT_SCORE) {
+        // Promote points nearby keys
+        score += ProximityInfoParams::LOCALMIN_DISTANCE_AND_NEAR_TO_KEY_SCORE;
+    }
+    // Angle
+    const float angle1 = GeometryUtils::getAngle(x, y, sampledInputXs->back(),
+            sampledInputYs->back());
+    const float angle2 = GeometryUtils::getAngle(sampledInputXs->back(), sampledInputYs->back(),
+            (*sampledInputXs)[size - 2], (*sampledInputYs)[size - 2]);
+    const float angleDiff = GeometryUtils::getAngleDiff(angle1, angle2);
+
+    // Save corner
+    if (distPrev > baseSampleRate * ProximityInfoParams::CORNER_CHECK_DISTANCE_THRESHOLD_SCALE
+            && (sumAngle > ProximityInfoParams::CORNER_SUM_ANGLE_THRESHOLD
+                    || angleDiff > ProximityInfoParams::CORNER_ANGLE_THRESHOLD_FOR_POINT_SCORE)) {
+        score += ProximityInfoParams::CORNER_SCORE;
+    }
+    return score;
+}
+
+// Sampling touch point and pushing information to vectors.
+// Returning if previous point is popped or not.
+/* static */ bool ProximityInfoStateUtils::pushTouchPoint(const ProximityInfo *const proximityInfo,
+        const int maxPointToKeyLength, const int inputIndex, const int nodeCodePoint, int x, int y,
+        const int time, const bool isGeometric, const bool doSampling,
+        const bool isLastPoint, const float sumAngle,
+        NearKeysDistanceMap *const currentNearKeysDistances,
+        const NearKeysDistanceMap *const prevNearKeysDistances,
+        const NearKeysDistanceMap *const prevPrevNearKeysDistances,
+        std::vector<int> *sampledInputXs, std::vector<int> *sampledInputYs,
+        std::vector<int> *sampledInputTimes, std::vector<int> *sampledLengthCache,
+        std::vector<int> *sampledInputIndice) {
+    const int mostCommonKeyWidth = proximityInfo->getMostCommonKeyWidth();
+
+    size_t size = sampledInputXs->size();
+    bool popped = false;
+    if (nodeCodePoint < 0 && doSampling) {
+        const float nearest = updateNearKeysDistances(proximityInfo, maxPointToKeyLength, x, y,
+                isGeometric, currentNearKeysDistances);
+        const float score = getPointScore(mostCommonKeyWidth, x, y, time, isLastPoint, nearest,
+                sumAngle, currentNearKeysDistances, prevNearKeysDistances,
+                prevPrevNearKeysDistances, sampledInputXs, sampledInputYs);
+        if (score < 0) {
+            // Pop previous point because it would be useless.
+            popInputData(sampledInputXs, sampledInputYs, sampledInputTimes, sampledLengthCache,
+                    sampledInputIndice);
+            size = sampledInputXs->size();
+            popped = true;
+        } else {
+            popped = false;
+        }
+        // Check if the last point should be skipped.
+        if (isLastPoint && size > 0) {
+            if (GeometryUtils::getDistanceInt(x, y, sampledInputXs->back(), sampledInputYs->back())
+                    * ProximityInfoParams::LAST_POINT_SKIP_DISTANCE_SCALE < mostCommonKeyWidth) {
+                // This point is not used because it's too close to the previous point.
+                if (DEBUG_GEO_FULL) {
+                    AKLOGI("p0: size = %zd, x = %d, y = %d, lx = %d, ly = %d, dist = %d, "
+                           "width = %d", size, x, y, sampledInputXs->back(),
+                           sampledInputYs->back(), GeometryUtils::getDistanceInt(
+                                   x, y, sampledInputXs->back(), sampledInputYs->back()),
+                           mostCommonKeyWidth
+                                   / ProximityInfoParams::LAST_POINT_SKIP_DISTANCE_SCALE);
+                }
+                return popped;
+            }
+        }
+    }
+
+    if (nodeCodePoint >= 0 && (x < 0 || y < 0)) {
+        const int keyId = proximityInfo->getKeyIndexOf(nodeCodePoint);
+        if (keyId >= 0) {
+            x = proximityInfo->getKeyCenterXOfKeyIdG(keyId, NOT_AN_INDEX, isGeometric);
+            y = proximityInfo->getKeyCenterYOfKeyIdG(keyId, NOT_AN_INDEX, isGeometric);
+        }
+    }
+
+    // Pushing point information.
+    if (size > 0) {
+        sampledLengthCache->push_back(
+                sampledLengthCache->back() + GeometryUtils::getDistanceInt(
+                        x, y, sampledInputXs->back(), sampledInputYs->back()));
+    } else {
+        sampledLengthCache->push_back(0);
+    }
+    sampledInputXs->push_back(x);
+    sampledInputYs->push_back(y);
+    sampledInputTimes->push_back(time);
+    sampledInputIndice->push_back(inputIndex);
+    if (DEBUG_GEO_FULL) {
+        AKLOGI("pushTouchPoint: x = %03d, y = %03d, time = %d, index = %d, popped ? %01d",
+                x, y, time, inputIndex, popped);
+    }
+    return popped;
+}
+
+/* static */ float ProximityInfoStateUtils::calculateBeelineSpeedRate(const int mostCommonKeyWidth,
+        const float averageSpeed, const int id, const int inputSize, const int *const xCoordinates,
+        const int *const yCoordinates, const int *times, const int sampledInputSize,
+        const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs,
+        const std::vector<int> *const sampledInputIndices) {
+    if (sampledInputSize <= 0 || averageSpeed < 0.001f) {
+        if (DEBUG_SAMPLING_POINTS) {
+            AKLOGI("--- invalid state: cancel. size = %d, ave = %f",
+                    sampledInputSize, averageSpeed);
+        }
+        return 1.0f;
+    }
+    const int lookupRadius = mostCommonKeyWidth
+            * ProximityInfoParams::LOOKUP_RADIUS_PERCENTILE / MAX_PERCENTILE;
+    const int x0 = (*sampledInputXs)[id];
+    const int y0 = (*sampledInputYs)[id];
+    const int actualInputIndex = (*sampledInputIndices)[id];
+    int tempTime = 0;
+    int tempBeelineDistance = 0;
+    int start = actualInputIndex;
+    // lookup forward
+    while (start > 0 && tempBeelineDistance < lookupRadius) {
+        tempTime += times[start] - times[start - 1];
+        --start;
+        tempBeelineDistance = GeometryUtils::getDistanceInt(x0, y0, xCoordinates[start],
+                yCoordinates[start]);
+    }
+    // Exclusive unless this is an edge point
+    if (start > 0 && start < actualInputIndex) {
+        ++start;
+    }
+    tempTime= 0;
+    tempBeelineDistance = 0;
+    int end = actualInputIndex;
+    // lookup backward
+    while (end < (inputSize - 1) && tempBeelineDistance < lookupRadius) {
+        tempTime += times[end + 1] - times[end];
+        ++end;
+        tempBeelineDistance = GeometryUtils::getDistanceInt(x0, y0, xCoordinates[end],
+                yCoordinates[end]);
+    }
+    // Exclusive unless this is an edge point
+    if (end > actualInputIndex && end < (inputSize - 1)) {
+        --end;
+    }
+
+    if (start >= end) {
+        if (DEBUG_DOUBLE_LETTER) {
+            AKLOGI("--- double letter: start == end %d", start);
+        }
+        return 1.0f;
+    }
+
+    const int x2 = xCoordinates[start];
+    const int y2 = yCoordinates[start];
+    const int x3 = xCoordinates[end];
+    const int y3 = yCoordinates[end];
+    const int beelineDistance = GeometryUtils::getDistanceInt(x2, y2, x3, y3);
+    int adjustedStartTime = times[start];
+    if (start == 0 && actualInputIndex == 0 && inputSize > 1) {
+        adjustedStartTime += ProximityInfoParams::FIRST_POINT_TIME_OFFSET_MILLIS;
+    }
+    int adjustedEndTime = times[end];
+    if (end == (inputSize - 1) && inputSize > 1) {
+        adjustedEndTime -= ProximityInfoParams::FIRST_POINT_TIME_OFFSET_MILLIS;
+    }
+    const int time = adjustedEndTime - adjustedStartTime;
+    if (time <= 0) {
+        return 1.0f;
+    }
+
+    if (time >= ProximityInfoParams::STRONG_DOUBLE_LETTER_TIME_MILLIS){
+        return 0.0f;
+    }
+    if (DEBUG_DOUBLE_LETTER) {
+        AKLOGI("--- (%d, %d) double letter: start = %d, end = %d, dist = %d, time = %d,"
+                " speed = %f, ave = %f, val = %f, start time = %d, end time = %d",
+                id, (*sampledInputIndices)[id], start, end, beelineDistance, time,
+                (static_cast<float>(beelineDistance) / static_cast<float>(time)), averageSpeed,
+                ((static_cast<float>(beelineDistance) / static_cast<float>(time))
+                        / averageSpeed), adjustedStartTime, adjustedEndTime);
+    }
+    // Offset 1%
+    // TODO: Detect double letter more smartly
+    return 0.01f + static_cast<float>(beelineDistance) / static_cast<float>(time) / averageSpeed;
+}
+
+/* static */ float ProximityInfoStateUtils::getPointAngle(
+        const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs, const int index) {
+    if (!sampledInputXs || !sampledInputYs) {
+        return 0.0f;
+    }
+    const int sampledInputSize = sampledInputXs->size();
+    if (index <= 0 || index >= sampledInputSize - 1) {
+        return 0.0f;
+    }
+    const float previousDirection = getDirection(sampledInputXs, sampledInputYs, index - 1, index);
+    const float nextDirection = getDirection(sampledInputXs, sampledInputYs, index, index + 1);
+    const float directionDiff = GeometryUtils::getAngleDiff(previousDirection, nextDirection);
+    return directionDiff;
+}
+
+/* static */ float ProximityInfoStateUtils::getPointsAngle(
+        const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs,
+        const int index0, const int index1, const int index2) {
+    if (!sampledInputXs || !sampledInputYs) {
+        return 0.0f;
+    }
+    const int sampledInputSize = sampledInputXs->size();
+    if (index0 < 0 || index0 > sampledInputSize - 1) {
+        return 0.0f;
+    }
+    if (index1 < 0 || index1 > sampledInputSize - 1) {
+        return 0.0f;
+    }
+    if (index2 < 0 || index2 > sampledInputSize - 1) {
+        return 0.0f;
+    }
+    const float previousDirection = getDirection(sampledInputXs, sampledInputYs, index0, index1);
+    const float nextDirection = getDirection(sampledInputXs, sampledInputYs, index1, index2);
+    return GeometryUtils::getAngleDiff(previousDirection, nextDirection);
+}
+
+// This function basically converts from a length to an edit distance. Accordingly, it's obviously
+// wrong to compare with mMaxPointToKeyLength.
+/* static */ float ProximityInfoStateUtils::getPointToKeyByIdLength(const float maxPointToKeyLength,
+        const std::vector<float> *const sampledNormalizedSquaredLengthCache, const int keyCount,
+        const int inputIndex, const int keyId) {
+    if (keyId != NOT_AN_INDEX) {
+        const int index = inputIndex * keyCount + keyId;
+        return std::min((*sampledNormalizedSquaredLengthCache)[index], maxPointToKeyLength);
+    }
+    // If the char is not a key on the keyboard then return the max length.
+    return static_cast<float>(MAX_VALUE_FOR_WEIGHTING);
+}
+
+// Updates probabilities of aligning to some keys and skipping.
+// Word suggestion should be based on this probabilities.
+/* static */ void ProximityInfoStateUtils::updateAlignPointProbabilities(
+        const float maxPointToKeyLength, const int mostCommonKeyWidth, const int keyCount,
+        const int start, const int sampledInputSize, const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs,
+        const std::vector<float> *const sampledSpeedRates,
+        const std::vector<int> *const sampledLengthCache,
+        const std::vector<float> *const sampledNormalizedSquaredLengthCache,
+        const ProximityInfo *const proximityInfo,
+        std::vector<std::unordered_map<int, float>> *charProbabilities) {
+    charProbabilities->resize(sampledInputSize);
+    // Calculates probabilities of using a point as a correlated point with the character
+    // for each point.
+    for (int i = start; i < sampledInputSize; ++i) {
+        (*charProbabilities)[i].clear();
+        // First, calculates skip probability. Starts from MAX_SKIP_PROBABILITY.
+        // Note that all values that are multiplied to this probability should be in [0.0, 1.0];
+        float skipProbability = ProximityInfoParams::MAX_SKIP_PROBABILITY;
+
+        const float currentAngle = getPointAngle(sampledInputXs, sampledInputYs, i);
+        const float speedRate = (*sampledSpeedRates)[i];
+
+        float nearestKeyDistance = static_cast<float>(MAX_VALUE_FOR_WEIGHTING);
+        for (int j = 0; j < keyCount; ++j) {
+            const float distance = getPointToKeyByIdLength(
+                    maxPointToKeyLength, sampledNormalizedSquaredLengthCache, keyCount, i, j);
+            if (distance < nearestKeyDistance) {
+                nearestKeyDistance = distance;
+            }
+        }
+
+        if (i == 0) {
+            skipProbability *= std::min(1.0f,
+                    nearestKeyDistance * ProximityInfoParams::NEAREST_DISTANCE_WEIGHT
+                            + ProximityInfoParams::NEAREST_DISTANCE_BIAS);
+            // Promote the first point
+            skipProbability *= ProximityInfoParams::SKIP_FIRST_POINT_PROBABILITY;
+        } else if (i == sampledInputSize - 1) {
+            skipProbability *= std::min(1.0f,
+                    nearestKeyDistance * ProximityInfoParams::NEAREST_DISTANCE_WEIGHT_FOR_LAST
+                            + ProximityInfoParams::NEAREST_DISTANCE_BIAS_FOR_LAST);
+            // Promote the last point
+            skipProbability *= ProximityInfoParams::SKIP_LAST_POINT_PROBABILITY;
+        } else {
+            // If the current speed is relatively slower than adjacent keys, we promote this point.
+            if ((*sampledSpeedRates)[i - 1] - ProximityInfoParams::SPEED_MARGIN > speedRate
+                    && speedRate
+                            < (*sampledSpeedRates)[i + 1] - ProximityInfoParams::SPEED_MARGIN) {
+                if (currentAngle < ProximityInfoParams::CORNER_ANGLE_THRESHOLD) {
+                    skipProbability *= std::min(1.0f, speedRate
+                            * ProximityInfoParams::SLOW_STRAIGHT_WEIGHT_FOR_SKIP_PROBABILITY);
+                } else {
+                    // If the angle is small enough, we promote this point more. (e.g. pit vs put)
+                    skipProbability *= std::min(1.0f,
+                            speedRate * ProximityInfoParams::SPEED_WEIGHT_FOR_SKIP_PROBABILITY
+                                    + ProximityInfoParams::MIN_SPEED_RATE_FOR_SKIP_PROBABILITY);
+                }
+            }
+
+            skipProbability *= std::min(1.0f,
+                    speedRate * nearestKeyDistance * ProximityInfoParams::NEAREST_DISTANCE_WEIGHT
+                            + ProximityInfoParams::NEAREST_DISTANCE_BIAS);
+
+            // Adjusts skip probability by a rate depending on angle.
+            // ANGLE_RATE of skipProbability is adjusted by current angle.
+            skipProbability *= (M_PI_F - currentAngle) / M_PI_F * ProximityInfoParams::ANGLE_WEIGHT
+                    + (1.0f - ProximityInfoParams::ANGLE_WEIGHT);
+            if (currentAngle > ProximityInfoParams::DEEP_CORNER_ANGLE_THRESHOLD) {
+                skipProbability *= ProximityInfoParams::SKIP_DEEP_CORNER_PROBABILITY;
+            }
+            // We assume the angle of this point is the angle for point[i], point[i - 2]
+            // and point[i - 3]. The reason why we don't use the angle for point[i], point[i - 1]
+            // and point[i - 2] is this angle can be more affected by the noise.
+            const float prevAngle = getPointsAngle(sampledInputXs, sampledInputYs, i, i - 2, i - 3);
+            if (i >= 3 && prevAngle < ProximityInfoParams::STRAIGHT_ANGLE_THRESHOLD
+                    && currentAngle > ProximityInfoParams::CORNER_ANGLE_THRESHOLD) {
+                skipProbability *= ProximityInfoParams::SKIP_CORNER_PROBABILITY;
+            }
+        }
+
+        // probabilities must be in [0.0, ProximityInfoParams::MAX_SKIP_PROBABILITY];
+        ASSERT(skipProbability >= 0.0f);
+        ASSERT(skipProbability <= ProximityInfoParams::MAX_SKIP_PROBABILITY);
+        (*charProbabilities)[i][NOT_AN_INDEX] = skipProbability;
+
+        // Second, calculates key probabilities by dividing the rest probability
+        // (1.0f - skipProbability).
+        const float inputCharProbability = 1.0f - skipProbability;
+
+        const float speedMultipliedByAngleRate = std::min(speedRate * currentAngle / M_PI_F
+                * ProximityInfoParams::SPEEDxANGLE_WEIGHT_FOR_STANDARD_DEVIATION,
+                        ProximityInfoParams::MAX_SPEEDxANGLE_RATE_FOR_STANDARD_DEVIATION);
+        const float speedMultipliedByNearestKeyDistanceRate = std::min(
+                speedRate * nearestKeyDistance
+                        * ProximityInfoParams::SPEEDxNEAREST_WEIGHT_FOR_STANDARD_DEVIATION,
+                                ProximityInfoParams::MAX_SPEEDxNEAREST_RATE_FOR_STANDARD_DEVIATION);
+        const float sigma = (speedMultipliedByAngleRate + speedMultipliedByNearestKeyDistanceRate
+                + ProximityInfoParams::MIN_STANDARD_DEVIATION) * mostCommonKeyWidth;
+        float theta = 0.0f;
+        // TODO: Use different metrics to compute sigmas.
+        float sigmaX = sigma;
+        float sigmaY = sigma;
+        if (i == 0 && i != sampledInputSize - 1) {
+            // First point
+            theta = getDirection(sampledInputXs, sampledInputYs, i + 1, i);
+            sigmaX *= ProximityInfoParams::STANDARD_DEVIATION_X_WEIGHT_FOR_FIRST;
+            sigmaY *= ProximityInfoParams::STANDARD_DEVIATION_Y_WEIGHT_FOR_FIRST;
+        } else {
+            if (i == sampledInputSize - 1) {
+                // Last point
+                sigmaX *= ProximityInfoParams::STANDARD_DEVIATION_X_WEIGHT_FOR_LAST;
+                sigmaY *= ProximityInfoParams::STANDARD_DEVIATION_Y_WEIGHT_FOR_LAST;
+            } else {
+                sigmaX *= ProximityInfoParams::STANDARD_DEVIATION_X_WEIGHT;
+                sigmaY *= ProximityInfoParams::STANDARD_DEVIATION_Y_WEIGHT;
+            }
+            theta = getDirection(sampledInputXs, sampledInputYs, i, i - 1);
+        }
+        NormalDistribution2D distribution((*sampledInputXs)[i], sigmaX, (*sampledInputYs)[i],
+                sigmaY, theta);
+        // Summing up probability densities of all near keys.
+        float sumOfProbabilityDensities = 0.0f;
+        for (int j = 0; j < keyCount; ++j) {
+            sumOfProbabilityDensities += distribution.getProbabilityDensity(
+                    proximityInfo->getKeyCenterXOfKeyIdG(j,
+                            NOT_A_COORDINATE /* referencePointX */, true /* isGeometric */),
+                    proximityInfo->getKeyCenterYOfKeyIdG(j,
+                            NOT_A_COORDINATE /* referencePointY */, true /* isGeometric */));
+        }
+
+        // Split the probability of an input point to keys that are close to the input point.
+        for (int j = 0; j < keyCount; ++j) {
+            const float probabilityDensity = distribution.getProbabilityDensity(
+                    proximityInfo->getKeyCenterXOfKeyIdG(j,
+                            NOT_A_COORDINATE /* referencePointX */, true /* isGeometric */),
+                    proximityInfo->getKeyCenterYOfKeyIdG(j,
+                            NOT_A_COORDINATE /* referencePointY */, true /* isGeometric */));
+            const float probability = inputCharProbability * probabilityDensity
+                    / sumOfProbabilityDensities;
+            (*charProbabilities)[i][j] = probability;
+        }
+    }
+
+    if (DEBUG_POINTS_PROBABILITY) {
+        for (int i = 0; i < sampledInputSize; ++i) {
+            std::stringstream sstream;
+            sstream << i << ", ";
+            sstream << "(" << (*sampledInputXs)[i] << ", " << (*sampledInputYs)[i] << "), ";
+            sstream << "Speed: "<< (*sampledSpeedRates)[i] << ", ";
+            sstream << "Angle: "<< getPointAngle(sampledInputXs, sampledInputYs, i) << ", \n";
+
+            for (std::unordered_map<int, float>::iterator it = (*charProbabilities)[i].begin();
+                    it != (*charProbabilities)[i].end(); ++it) {
+                if (it->first == NOT_AN_INDEX) {
+                    sstream << it->first
+                            << "(skip):"
+                            << it->second
+                            << "\n";
+                } else {
+                    sstream << it->first
+                            << "("
+                            //<< static_cast<char>(mProximityInfo->getCodePointOf(it->first))
+                            << "):"
+                            << it->second
+                            << "\n";
+                }
+            }
+            AKLOGI("%s", sstream.str().c_str());
+        }
+    }
+
+    // Decrease key probabilities of points which don't have the highest probability of that key
+    // among nearby points. Probabilities of the first point and the last point are not suppressed.
+    for (int i = std::max(start, 1); i < sampledInputSize; ++i) {
+        for (int j = i + 1; j < sampledInputSize; ++j) {
+            if (!suppressCharProbabilities(
+                    mostCommonKeyWidth, sampledInputSize, sampledLengthCache, i, j,
+                    charProbabilities)) {
+                break;
+            }
+        }
+        for (int j = i - 1; j >= std::max(start, 0); --j) {
+            if (!suppressCharProbabilities(
+                    mostCommonKeyWidth, sampledInputSize, sampledLengthCache, i, j,
+                    charProbabilities)) {
+                break;
+            }
+        }
+    }
+
+    // Converting from raw probabilities to log probabilities to calculate spatial distance.
+    for (int i = start; i < sampledInputSize; ++i) {
+        for (int j = 0; j < keyCount; ++j) {
+            std::unordered_map<int, float>::iterator it = (*charProbabilities)[i].find(j);
+            if (it == (*charProbabilities)[i].end()){
+                continue;
+            } else if(it->second < ProximityInfoParams::MIN_PROBABILITY) {
+                // Erases from near keys vector because it has very low probability.
+                (*charProbabilities)[i].erase(j);
+            } else {
+                it->second = -logf(it->second);
+            }
+        }
+        (*charProbabilities)[i][NOT_AN_INDEX] = -logf((*charProbabilities)[i][NOT_AN_INDEX]);
+    }
+}
+
+/* static */ void ProximityInfoStateUtils::updateSampledSearchKeySets(
+        const ProximityInfo *const proximityInfo, const int sampledInputSize,
+        const int lastSavedInputSize, const std::vector<int> *const sampledLengthCache,
+        const std::vector<std::unordered_map<int, float>> *const charProbabilities,
+        std::vector<NearKeycodesSet> *sampledSearchKeySets,
+        std::vector<std::vector<int>> *sampledSearchKeyVectors) {
+    sampledSearchKeySets->resize(sampledInputSize);
+    sampledSearchKeyVectors->resize(sampledInputSize);
+    const int readForwordLength = static_cast<int>(
+            hypotf(proximityInfo->getKeyboardWidth(), proximityInfo->getKeyboardHeight())
+                    * ProximityInfoParams::SEARCH_KEY_RADIUS_RATIO);
+    for (int i = 0; i < sampledInputSize; ++i) {
+        if (i >= lastSavedInputSize) {
+            (*sampledSearchKeySets)[i].reset();
+        }
+        for (int j = std::max(i, lastSavedInputSize); j < sampledInputSize; ++j) {
+            // TODO: Investigate if this is required. This may not fail.
+            if ((*sampledLengthCache)[j] - (*sampledLengthCache)[i] >= readForwordLength) {
+                break;
+            }
+            for(const auto& charProbability : charProbabilities->at(j)) {
+                if (charProbability.first == NOT_AN_INDEX) {
+                    continue;
+                }
+                (*sampledSearchKeySets)[i].set(charProbability.first);
+            }
+        }
+    }
+    const int keyCount = proximityInfo->getKeyCount();
+    for (int i = 0; i < sampledInputSize; ++i) {
+        std::vector<int> *searchKeyVector = &(*sampledSearchKeyVectors)[i];
+        searchKeyVector->clear();
+        for (int j = 0; j < keyCount; ++j) {
+            if ((*sampledSearchKeySets)[i].test(j)) {
+                const int keyCodePoint = proximityInfo->getCodePointOf(j);
+                if (std::find(searchKeyVector->begin(), searchKeyVector->end(), keyCodePoint)
+                        == searchKeyVector->end()) {
+                    searchKeyVector->push_back(keyCodePoint);
+                }
+            }
+        }
+    }
+}
+
+// Decreases char probabilities of index0 by checking probabilities of a near point (index1) and
+// increases char probabilities of index1 by checking probabilities of index0.
+/* static */ bool ProximityInfoStateUtils::suppressCharProbabilities(const int mostCommonKeyWidth,
+        const int sampledInputSize, const std::vector<int> *const lengthCache,
+        const int index0, const int index1,
+        std::vector<std::unordered_map<int, float>> *charProbabilities) {
+    ASSERT(0 <= index0 && index0 < sampledInputSize);
+    ASSERT(0 <= index1 && index1 < sampledInputSize);
+    const float keyWidthFloat = static_cast<float>(mostCommonKeyWidth);
+    const float diff = fabsf(static_cast<float>((*lengthCache)[index0] - (*lengthCache)[index1]));
+    if (diff > keyWidthFloat * ProximityInfoParams::SUPPRESSION_LENGTH_WEIGHT) {
+        return false;
+    }
+    const float suppressionRate = ProximityInfoParams::MIN_SUPPRESSION_RATE
+            + diff / keyWidthFloat / ProximityInfoParams::SUPPRESSION_LENGTH_WEIGHT
+                    * ProximityInfoParams::SUPPRESSION_WEIGHT;
+    for (std::unordered_map<int, float>::iterator it = (*charProbabilities)[index0].begin();
+            it != (*charProbabilities)[index0].end(); ++it) {
+        std::unordered_map<int, float>::iterator it2 = (*charProbabilities)[index1].find(it->first);
+        if (it2 != (*charProbabilities)[index1].end() && it->second < it2->second) {
+            const float newProbability = it->second * suppressionRate;
+            const float suppression = it->second - newProbability;
+            it->second = newProbability;
+            // mCharProbabilities[index0][NOT_AN_INDEX] is the probability of skipping this point.
+            (*charProbabilities)[index0][NOT_AN_INDEX] += suppression;
+
+            // Add the probability of the same key nearby index1
+            const float probabilityGain = std::min(suppression
+                    * ProximityInfoParams::SUPPRESSION_WEIGHT_FOR_PROBABILITY_GAIN,
+                    (*charProbabilities)[index1][NOT_AN_INDEX]
+                            * ProximityInfoParams::SKIP_PROBABALITY_WEIGHT_FOR_PROBABILITY_GAIN);
+            it2->second += probabilityGain;
+            (*charProbabilities)[index1][NOT_AN_INDEX] -= probabilityGain;
+        }
+    }
+    return true;
+}
+
+/* static */ bool ProximityInfoStateUtils::checkAndReturnIsContinuousSuggestionPossible(
+        const int inputSize, const int *const xCoordinates, const int *const yCoordinates,
+        const int *const times, const int sampledInputSize,
+        const std::vector<int> *const sampledInputXs, const std::vector<int> *const sampledInputYs,
+        const std::vector<int> *const sampledTimes,
+        const std::vector<int> *const sampledInputIndices) {
+    if (inputSize < sampledInputSize) {
+        return false;
+    }
+    for (int i = 0; i < sampledInputSize; ++i) {
+        const int index = (*sampledInputIndices)[i];
+        if (index >= inputSize) {
+            return false;
+        }
+        if (xCoordinates[index] != (*sampledInputXs)[i]
+                || yCoordinates[index] != (*sampledInputYs)[i]) {
+            return false;
+        }
+        if (!times) {
+            continue;
+        }
+        if (times[index] != (*sampledTimes)[i]) {
+            return false;
+        }
+    }
+    return true;
+}
+
+// Get a word that is detected by tracing the most probable string into codePointBuf and
+// returns probability of generating the word.
+/* static */ float ProximityInfoStateUtils::getMostProbableString(
+        const ProximityInfo *const proximityInfo, const int sampledInputSize,
+        const std::vector<std::unordered_map<int, float>> *const charProbabilities,
+        int *const codePointBuf) {
+    ASSERT(sampledInputSize >= 0);
+    memset(codePointBuf, 0, sizeof(codePointBuf[0]) * MAX_WORD_LENGTH);
+    int index = 0;
+    float sumLogProbability = 0.0f;
+    // TODO: Current implementation is greedy algorithm. DP would be efficient for many cases.
+    for (int i = 0; i < sampledInputSize && index < MAX_WORD_LENGTH - 1; ++i) {
+        float minLogProbability = static_cast<float>(MAX_VALUE_FOR_WEIGHTING);
+        int character = NOT_AN_INDEX;
+        for (std::unordered_map<int, float>::const_iterator it = (*charProbabilities)[i].begin();
+                it != (*charProbabilities)[i].end(); ++it) {
+            const float logProbability = (it->first != NOT_AN_INDEX)
+                    ? it->second + ProximityInfoParams::DEMOTION_LOG_PROBABILITY : it->second;
+            if (logProbability < minLogProbability) {
+                minLogProbability = logProbability;
+                character = it->first;
+            }
+        }
+        if (character != NOT_AN_INDEX) {
+            const int codePoint = proximityInfo->getCodePointOf(character);
+            if (codePoint == NOT_A_CODE_POINT) {
+                AKLOGE("Key index(%d) is not found. Cannot construct most probable string",
+                        character);
+                ASSERT(false);
+                // Make the length zero, which means most probable string won't be used.
+                index = 0;
+                break;
+            }
+            codePointBuf[index] = codePoint;
+            index++;
+        }
+        sumLogProbability += minLogProbability;
+    }
+    codePointBuf[index] = '\0';
+    return sumLogProbability;
+}
+
+/* static */ void ProximityInfoStateUtils::dump(const bool isGeometric, const int inputSize,
+        const int *const inputXCoordinates, const int *const inputYCoordinates,
+        const int sampledInputSize, const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs,
+        const std::vector<int> *const sampledTimes,
+        const std::vector<float> *const sampledSpeedRates,
+        const std::vector<int> *const sampledBeelineSpeedPercentiles) {
+    if (DEBUG_GEO_FULL) {
+        for (int i = 0; i < sampledInputSize; ++i) {
+            AKLOGI("Sampled(%d): x = %d, y = %d, time = %d", i, (*sampledInputXs)[i],
+                    (*sampledInputYs)[i], sampledTimes ? (*sampledTimes)[i] : -1);
+        }
+    }
+
+    std::stringstream originalX, originalY, sampledX, sampledY;
+    for (int i = 0; i < inputSize; ++i) {
+        originalX << inputXCoordinates[i];
+        originalY << inputYCoordinates[i];
+        if (i != inputSize - 1) {
+            originalX << ";";
+            originalY << ";";
+        }
+    }
+    AKLOGI("===== sampled points =====");
+    for (int i = 0; i < sampledInputSize; ++i) {
+        if (isGeometric) {
+            AKLOGI("%d: x = %d, y = %d, time = %d, relative speed = %.4f, beeline speed = %d",
+                    i, (*sampledInputXs)[i], (*sampledInputYs)[i], (*sampledTimes)[i],
+                    (*sampledSpeedRates)[i], (*sampledBeelineSpeedPercentiles)[i]);
+        }
+        sampledX << (*sampledInputXs)[i];
+        sampledY << (*sampledInputYs)[i];
+        if (i != sampledInputSize - 1) {
+            sampledX << ";";
+            sampledY << ";";
+        }
+    }
+    AKLOGI("original points:\n%s, %s,\nsampled points:\n%s, %s,\n",
+            originalX.str().c_str(), originalY.str().c_str(), sampledX.str().c_str(),
+            sampledY.str().c_str());
+}
+} // namespace latinime